Interaction of Bifidobacteria with Ferric Iron

• Published in: International dairy journal 1998-05, Vol.8 (5), p.507-512
• Main Authors: Bezkorovainy, Anatoly, Kot, Eva
• Format: Article
• Language: English
• Subjects: Bacteriology; bifidobacteria; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; Food industries; Food microbiology; free radicals; Fundamental and applied biological sciences. Psychology; iron; Metabolism. Enzymes; Microbiology; Mission oriented research; Physiology and metabolism; probiotics
• ISSN: 0958-6946; 1879-0143
• DOI: 10.1016/S0958-6946(98)00078-8

Bifidobacteria are probiotics that have been implicated in a number of beneficial actions in humans and animals. It is estimated that 20–30% of bifidobacteria consumed will enter the colon from the ileum, and that this quantity is sufficient to exert an influence on colon physiology. There are many reasons why probiotics exert a beneficial effect on their host organism. This paper focuses on one of them: the interaction of bifidobacteria with ferric iron in the form of Fe(OH) 3 and iron-saturated lactoferrin. Lactoferrin can donate its iron to Bifidobacterium breve for growth purposes, and so can its C-terminal domain fragment. Fe(OH) 3 is surface-bound by Bifidobacterium thermophilum in a biphasic manner: the rapid initial phase and a slower process, the extent of which may depend on the presence of free radicals in the medium. The latter alter the bacterial surface, resulting in greater binding of Fe(OH) 3 by the bacteria. Free radical scavengers such as lactate and glucose counteract cell surface damage and lower the extent of Fe(OH) 3 binding. Free radicals thus serve to increase iron binding by bifidobacteria making it less available to pathogens.